Evoked Responses Recorded From the Depths of the Human Brain

Brazier, Mary A. B.

doi:10.1111/j.1749-6632.1964.tb26741.x

Cited by 128 publications

(31 citation statements)

References 23 publications

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“…It was found that limbic structures such as the amygdalae, the anterior and posterior hippocampi and the anterior cingulate gyri are very potent ipsilateral modulators of bilateral electrodermal activity as opposed to neocortical sites such as the mid-region of the second temporal gyri Beuzeron-Mangina, 1994, 1996). The fact that high ipsilateral electrodermal responses were obtained when limbic structures were electrically stimulated is not surprising since direct pathways connecting the left and right limbic structures are very limited in humans and in primates (Amaral et al, 1984;Brazier, 1964;Lieb et al, 1986Lieb et al, , 1987Pandya and Rosene, 1985;Wilson et al, 1987). As we descend the phylogenetic scale, strong functional connections between left and right limbic structures of the cat, rabbit and rat do exist (Andersen, 1959, Hjorth-Simonsen, 1977Ramon y Cajal, 1909, 1911 as opposed to, when ascending the phylogenetic scale to monkeys and humans (Brazier, 1964;Wilson et al, 1987).…”

Section: Direct Electrical Stimulation Of Specific Human Brain Structmentioning

confidence: 89%

Neuronal plasticity in memory and learning abilities: Theoretical position and selective review

Mangina¹,

Sokolov

2006

International Journal of Psychophysiology

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Section: Direct Electrical Stimulation Of Specific Human Brain Structmentioning

confidence: 89%

Neuronal plasticity in memory and learning abilities: Theoretical position and selective review

Mangina¹,

Sokolov

2006

International Journal of Psychophysiology

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“…Conversely, signal averaging can also conceal trial-by-trial variability of evoked response characteristics. For example, if evoked response strength is invariant but response latency changes on single trials, then the averaged signal will be distorted and with lower amplitude (Brazier, 1964). Secondly, variations in amplitude between two averaged ERFs, may not reflect differences in single trial response strength but rather, differences in the proportion of trials with a response of constant amplitude (Otten & Rugg, 2005).…”

Section: Discussionmentioning

confidence: 99%

“…less precision) in the timing of evoked responses than another, then averaged evoked response amplitudes (i.e. ERF amplitudes) may differ even though peak amplitudes of single trial responses are identical for both conditions (Brazier, 1964). …”

Section: Methodsmentioning

confidence: 99%

Evidence for an all-or-none perceptual response: single-trial analyses of magnetoencephalography signals indicate an abrupt transition between visual perception and its absence

2012

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Whether consciousness is an all-or-none or graded phenomenon is an area of inquiry that has received considerable interest in neuroscience and is as of yet, still debated. In this magnetoencephalography (MEG) study we used a single stimulus paradigm with sub-threshold, threshold and supra-threshold duration inputs to assess whether stimulus perception is continuous with or abruptly differentiated from unconscious stimulus processing in the brain. By grouping epochs according to stimulus identification accuracy and exposure duration, we were able to investigate whether a high-amplitude perception-related cortical event was (1) only evoked for conditions where perception was most probable (2) had invariant amplitude once evoked and (3) was largely absent for conditions where perception was least probable (criteria satisfying an all-on-none hypothesis). We found that averaged evoked responses showed a gradual increase in amplitude with increasing perceptual strength. However, single trial analyses demonstrated that stimulus perception was correlated with an all-or-none response, the temporal precision of which increased systematically as perception transitioned from ambiguous to robust states. Due to poor signal-to-noise resolution of single trial data, whether perception-related responses, whenever present, were invariant in amplitude could not be unambiguously demonstrated. However, our findings strongly suggest that visual perception of simple stimuli is associated with an all-or-none cortical evoked response the temporal precision of which varies as a function of perceptual strength.

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“…This simple averaging technique is based on the assumption that the ERP is a deterministic signal, relative to the stimulus onset. However, previous research has shown that many aspects of the ERP (in particular, the peak latency and amplitude) are highly variable across trials (Brazier, 1964). In addition, there may be systematic, physiologically meaningful changes of the ERP as time passes.…”

Section: Introductionmentioning

confidence: 98%